Wired music distribution system



July 28, 1942. R. L. STARK ETAL 2912115 WIREDv MUSIC DISTRIBUTION SYSTEMFiled Aug. 3, 1940 1o sleets-sheet 1 TTT A INVENTORS Easier Z.. Sme/fo/VAQD L. 5y/QE@ ATTORNEYS.

July 28, 1942.

R. l.. s'rARK ETAL WIRED MUSIC DISTRIBUTION SYSTEM Filed Aug. 3, 1940 10Sheets-Sheet 2 l@ .INVENTORS ROBERT L. STARK ga/VAR@ L. LErPE/ ATTORNYS.

July 28 l942-l R. l.. STARK E-rm. 2,291,115

WIRED MUSIC DISTRIBUTION SYSTEM Filed Aug. 3, 1940I v 10 Sheets-Sheet 4INVENTORS Roemer L. STARK 1 a Il y f f 4 July 28 1942 I R. L. STARKE'rAL 2,291,115

WIRED MUSIC DISTRIBUTION SYSTEM l Filed Aug. 3, 1940 10 Sheets-Sheet 5 QINVENTORS Ros-.er L. STARK fo/vago L. LEwE/ By l 9- dgp. n ATTORNEYS.

Juy 2s, 1942. R. L. STARK Em 2,291,115

WIRED MUSIC lDISTRIBUTION SYSTEM Filed Aug. 3, 1940 .l0 Sheets-Sheet 6INVENTORS 57142K Eofer L LEONARD L. LEYREA? Y BY .4T ORNEY July2s,1942.R. L. STARK ETAL 2,291,115

WIRED MUSIC DISTRIBUTION SYSTEM Filed Aug. :5, 1940 -10 Smeets-sheet 'rINVENTORS Rosse? L.- STARK LEONARD L. LEYREE v BY `l ATTORN July 28,1942. R. 1 STARK. T AL 2,291,115

WIRED MUSIC DISTRIBUTION SYSTEM` Filed Aug. 3, 1940 10 Sheets-Sheei 8July 28, 1942. R. L.. STARK ET AL 2,291,115

WIRED MUSIC DISTRIBUTION SYSTEM Filed Aug. 5, 1940 l0 Sheets-Sheet 9 l257 F 5' 5.] T RELAY f PO WER JUPPL Y 336' o L 336 y; .T0125 Reef/e7' L.STARK 320 ATTORNEYS July 28, 1942.,

R. L. STARK ET Al.

WIRED MUSIC DISTRIBUTION SYSTEM Filed Aug. 5) 1940 10 Sheets-Sheet l0TTORNEYS Patented July 28, 1942 WIRED MUs'Io DIsTmBU'rI SYSTEM Robert L.stark, Los Angeles, and Leonard L. Leyrer, San Francisco, Calif.

Application August 3`, 1940, Serial No. 350,934

17 Claims.

Our invention relates to wired music distribution systems and moreparticularly to a system for distributing music to outlying stationsfrom a central location. Our system lis ideally adapted for coin controlfor the playing of phonograph records. l Among the objects of ourinvention are: To

provide musical entertainment in a plurality of outlying stationstransmitted from a single centralized location; to provide such a systemoperating over a single wire pair between the central location and eachoutlying station; to provide a remote controlled phonograph musicdistributing system having a practically unlimited source of availableselections; to provide a music distribution system incorporating apersonal element; to provide a coin controlled phonograph recordreproducer operated from a central station with 'two-way communicationtherewith; to provide such a system operating over a single pair ofwires; to provide a coin controlled phonograph reproducing systemremotely operated from a central location; to provide interconnectedphonograph reproducers in a plurality of locations; to provide a highfidelity remote control sound distribution system operating overcommercial telephone lines; to provide `a musical entertainment systemthat is simple and under the con. trol of a single centralized operator;to provide a coin operated sound distribution system giving anaccumulative record of coin values; to provide a two-way sounddistribution system operating from a central location; to provide a highfidelity coin controlled music distribution system.

Our invention possesses numerous other objects and features ofadvantage, some of which, together with the foregoing, will be set4forth in the following description of specific apparatus embodying andutilizing our novel method. It is therefore to be understood that ourmethod is applicable to other apparatus, and that we do not limitourselves, in any way, to Ithe apparatus of the present application, aswe may adopt various other apparatus embodiments, utilizing the method,within thescope of the appended claims.

Due to the desirability of providing music in public places such ascocktail parlors, hotel lobbies, railroad, ferry and-.bus stations, orin other places where the public congregates, coin operated automaticphonographs have been developed wherein a limited number of phonographrecords may be stacked and selectively played upon the insertionof theproper coin in the apparatus. The music provided by such a system isgenerally satisfactory, with the exception that the selections availableare always limited by the ability of the machine V-to handle yonly acertain limited number of records, and by the fact that such machinesare expensive, intricate, and therefore subject to relatively highservice charges. They are also completely impersonal, and it is one ofthe main objects of the present invention to provide a coin operatedmusic reproducer which can be installed in such public places asoutlined above,

operated from a central location to which a pluy rality of other similarreproducing stations are connected,- under the control of a humanoperator. Under such conditions the equipment which is utilized in thereproducing unit need only be a small fraction of that ordinarily usedin an automatic phonograph and therefore is much less subject to troubleand requires far less service. Furthermore, a central operator may -haveat her disposal, f or women are customarily used for this type of Work,a practically unlimited selection of records, so that the person whowishes music reproduced is able to select practically any record he orshe so desires.

'I'he assembly of the major portion of the equipment at a centralstation which may, for example, have as many as twenty outlyingstations, makes for ease of service and for ay great reduction in cost,both of initial installation and of operation. With personal attention,a human operator greatly increases the income of the coin operatedsystem and sustains tln interest of customers far beyond that of theautomatic phonograph. We have found that a system comprising twentyoutlying stations operated from one single, preferably, centrallocation, over wire pairs leased or otherwise obtained from the localtelephone company, forms a simple and efilcient system for distributingmusic for entertainment purposes, and one preferred form of such asystem will be described herein.

In the drawings:

Fig. 1 is a diagrammatic perspective view of thephysical units comprisedin thesystem of our invention, only one outlying station beingillustrated.`

Fig. 2 is a face View of a single coin recording and switch and pilotassembly, used by the central station operator.

Fig. 3 is a block diagram of the central station connected through asingle pair of wires to a n single reproducing station.

Fig. 4 is a preferred wiring diagram forl an outlying reproducingstation.

Fig. 5 is a partial diagram of a tone controlFlg.'lisawiringdiagramofthe central station voice amplifier lmits.

Fig. 8 is a wiring diagram of the for the stepper relay unit.

Fig. 9 is a wiring diagram circuit.

Fig. l is a wiring diagram of the phonograph pickup amplifier.

Fig. 11 is a tic view of a single phonograph turntable with motor switchand pilot light connections.

Fig. l2 isadiagramofacoinchutesignaling device that may ducing station.

Fig. 13 is a tic representation of the coin register stepper relay.

Fig. 14 is a circuit diagram of a control circuit thatc'an be used inconjunction with coin receivers located at a distance away from theoutlying stationscabinet.

Fig. 15 is a circuit diagram of the power supply and control .relays ofthe circuit shown in Fig. 14.

Pig.16isacircuitdiagramshowingamodi cation of the circuit oi Fig. 14. vi

Referring directly to Fig. 1 for a more detailed description of ourinvention, a reproducer cabinet il is provided. to be installed inwhatever public location is selected. This cabinet III is of attractivedesign and is provided on the front thereof with a grille I I throughwhich sound may pass from a loud-speaker in the cabinet, not shown. Alsoon the iront face of the cabinet we provide coin slides I2 as will befully described later. for the reception of nickels, dimes andtwenty-live cent pieces.' as is customary in coin controlled devices.The top Il of the-cabinet is preferably provided with a display surfaceI slanting downwardly to the front of the cabinet Il and on this displayface, we position a printed card Il carrying the titles of a largenumber of phonograph records, preferably each identiiied by a number.Also on the slanting display surface I5 we position a microphone grilleI1 backed by a microphone, not shown. Within cabinet I0 is positioned acoin switch, a microphone ampliner, a loud-speaker and speakeramplifier, and a balancing network, all not shown in this iigure, butto'be described later.

Running into the cabinet Il, and connecting with the apparatus therein.is a single pair oi wires 2l, leading to a central location and into adistribution block 2l to which other pairs are connected, these pairsgoing to other .reproducing cabinets in other public locations. Wiresfrom the reproducing block 2i enter a control board 22, this controlboard being provided with an operating face 2l, an operating shelf 24, amicrophone 25, reproducers 26 and pilot assemblies 21, and if desiredvolume controls, to be later described. The apparatus contained in .thiscentral board will be described later.

A cable 2l from the control board 22 to a turntable bank 2l having aplurality oi phonograph turntables Il mounted thereon, each with itsindividual reproducing arm II. The phonograph turntables Il arepreferably mounted on the turntable bank 2l on stepped ledges 32 with aslight overhang, to save space, and below each turntable is positioned arecord recess vowel'v Supply of the stepper relay circuit thereforoperating the,

be used at the outlying reproby the number or records desired to supplyyre. Vquirements of the type of music called for by the outlyingstations. In commercial installations of this type. Afrom 500 to 5,000records are usually kept in stock, each identiiled with a numbercorresponding to -the number accompanying the titles of the printedlists I6 at the outlying reproducing stations.

Before describing in detail the electrical circuits involved in thesetup just described, we believe that such circuits would be moreunderstandable i! the gross operation of the device be set out' at thispoint.

The usual complement of help at the central station during the busyhours, i. e., from 1l p. m. to 2 a. m., is two girls. One girl is seatedat the operating board 22 and the other girl is positionedV to load therecord -recesses 33 on the turntable bank 29, to load and start theturntables 30 and to take oil the played records and redistribute themin the record rack I4. It is convenient to utilize when twentyreproducing stations are utilized, three separate turntable banks. twooi' six turntables each, and one of nine, leaving one turntable free forsubstitution as a spare.

Let us assume that a customer at an outlying station desires musi Heinserts a coin in one or the coin slides I2. pushes in the proper coinslide. This action lights one or more pilot lights in the pilot lightassembly 21. corresponding to the outlying station at which the coin isinserted. The coin slide mechanism is such that the pilot lightsin'assembly 21 as shown in Fig. 2 are lighted in order and in numbercorresponding to the monetary value of the coin inserted. For example.ii ilve cents only is inserted, pilot light l! is illuminated. It tencents is inserted, pilot light 4I lights and pilot light 4l goes out. Ifilfteen cents is inserted, pilot light l2 is lighted, and so on inserial order through pilot lights 43, 44, 45, 46, and 41, these eightpilot lights being suiiicient to indicate the insertion oi forty centsat a time, which is the maximum value that can be inserted in the coinslides I2 at one time.

Upon seeing one of the pilot lights, 40 to 41 inclusive, remainilluminated, the operator moves the main control switch l0 to talkingposition and utilizing microphone 25, asks for the number of thephonograph record desired, this voice at the reproducing station comingthrough grille I I from the main loud-speaker. The operator then throwsswitch 50 to listening position, and the customer who by this time hasmade his selection, simply speaks in a normal voice in front o1' cabinetIl and gives the number or numbers of the phonograph selections desired,in accordance with the value of the coins he has inserted. The customersvoice is picked up by the microphone back of grille I1, and reproducedto the operator through 'the central station reproducers 2l. Theoperator writes down on a memo pad the numbers desired and either passesit,or tells these numbersv to the operator who is handling thephonograph turntables. The latter selects the record from rack u andplaces it on the turntable, to be played. 'Ihe music signals developedpass through the central board to the outlying reproducing station, withswitch 50 in a neutral position.

'The operator can at all times check the operationof the reproducingstation as to whether or not the music is being played, by turning themain key 58 to listening position, thereby hearing the music by echowithin the public place in which the music is being played, this echobeing picked up by the microphone behind grille |1,

If more than one record has been called for and paid for, as indicatedby the position of the pilot light 40 to 41 that remains illuminated,the operator tending the records picks out the proper number of recordsfrom rack 34 and stacks them below the proper turntable in recess 33,and as long as there is a record in recess 33, the record operator-knows that they arev entitled to be played. When there are no recordsin the recess 33 the record operator knows that all that have been paidfor have been played.

As soon as the control board operator has checked payment and obtainedthe numbers of the records called for by the customer, Ashe puts out theilluminated pilot light 40 to 41, by pushing a stepper relay releasebutton and throws her key 50 to neutral. She is, however, able to checkthe operation of the turntables directly from the operating board 22 asa turntable pilot light 52 is provided adjacent switch 50gwhich islit'at all times when the phonograph turntable corresponding to adjacentkey 50 is rotating. Also adjacent key 50 is a monitor switch 53 which isconnected to a power level indicator 54 mounted on the operating board.

Thus, the central operator can receive the calls from outlyingreproducing stations, check the money value inserted at the reproducingstation, talk to the reproducing station, and control the playback tothe reproducing station as Well as determine whether or not thatparticular station is actually in operation.

Having described the gross operation of the system, we will now describethe circuits utilized as shown beginning with Fig. 3, which is a blockdiagram showing the main units involved.

At the reproducing station, a 60cycle supply 68 Afeeds the coin switch6|, preferably through a step-down transformer winding 62 on power aturntable motor supply line 9|. Transformer transformer 62P to supply 24volts to the coin switch. The coin switch output line 63 feeds into anetwork 61 on the network side of a network transformer 64, fed bymicrophone amplifier 65 under the control of microphone 66 placed backof grille |1 in the reproducing cabinet I8 as shown in Fig. 1. Networktransformer 64 and line 63 feed into a balancing network 61, thisbalancing network feeding laterally into a second network transformer 68which inturn feeds -into a loudspeaker amplier 69 supplying power to themain loudspeaker 10 placed back of speaker grille I I of reproducingcabinet I8.

The line leg 1| from the balancing network passes intol an isolationtransformer 12v and thence to a two-wire line 13 leading to the centralstation. At the central station the line 13 enters a central stationisolation transformer 14 which feeds a central station balancing network15. One side of this balancing network 16 goes through the usual`network transformer 18 into output line 80, this output line beingdivided and going one way through a 60cycle lter and rectifier 8| into astepper relay contro1 82, the output of which is led to a stepper relaysolenoid B3 for actuation of a stepper relay mechanism which energizespilot lights 40 to 41 inclusive, later to be described.

Output line 80 is also led through listening contacts 58L' of switch 58to central station speaker amplifier 85 which energizes central stationspeakers '26 on central board 22. The other lateral leg 86 of balancingnetwork 15 is connected to network transformer 61, which is fed by areproducer amplifier 88 energized by a phonograph reproducer 89operating in conjunction with turntable 38 driven by turntable motor 98from 81`is also fed through the talking vcontacts 50T of switch 50 froma central station microphone amplifier 92 controlled by central stationmicrophone 25.

In Fig. 4, we have shown the wiring diagram of a complete outlyingreproducing station. Here the microphone 66 feeds into microphoneamplifier 65 through input transformer |00. 'This microphone amplifieris a conventional cascade resistance coupled amplifier, all circuitsexcept the cathode heater circuits being shown, comprising triodes |0|,|02, and |83 coupled by the customary resistance groups |04 and |85. andhaving a volume control resistor |01 between first and second tubes |0|and |02. The last tube of the microphone amplifier 65 feeds into networktransformer 64 through line |06 and thence into balancing network 61,and to main line 13 through transformer 12. Line |06 is also suppliedwith 60cycle current through line 63. Line |86, therefore, can carry thevoice signal from microphone 66 and also 60 cycles under control of coinswitch 6|. One leg |08 of line |06 connects directly to one side of mainline transformer 12,

lwhereas the other leg |09 of line |86 connects to the other side oftransformer 12 through a variable resistor I8 shunted by capacityTransformer 12 is shunted vby shunt resistor ||2. Connection ||4 is madefrom one side of transformer 12 directly to lateral network transformer68,

the other side of transformer 12 being connected to transformer 68through a series resistor ||5. Leg |89 is cross-connected to thetransformer end of resistor ||5 by cross-resistor I|6. Thus, music fromthe central station carried by line 13 will pass to loud-speaker amplier69. We have found that a practical balancing network may have allconnected transformer elements, for example, and all resistors except||0,l measuring 500 ohms, and we prefer to make resistor ||0, 750 ohmsshunted by .l mfd. capacity. Such a balancing network may be adjusted byadjusting thevalue of resistor ||0, so that there is minimum feedbackbetween microphone 66 and loudl speaker 18 through amplier 69, andminimum 60cycle transfer to amplifier 69, so that the 60 cycles may bepassed outwardly with minimum interference with any music signals thatmight be coming in.

Amplifier 69 is fed from network transformer 68 through a'potentiometervolumecontrol |28, this volume control having separate connections |2|which can be used for the insertion of a remote volume `control ifdesired. The incoming music signals are then passed to a double triodeinput tube |22, the anodes |23 of which feed through resistance |24, apair of push-pull output tubes |25 and |26. The output of these lattertubes is passed through an output transformer |21, the secondary |28 ofoutput transformer |21 being divided by a center tap |29 into a pair ofseparate output circuits. A 4-ohm circuit leads to a 4ohm socket |30,and a combined or8- ohm circuit leads to an 8ohm socket |3|. Loudspeaker10 preferably is a dynamic type operated by voice coil |32 as iscustomary in the art, and has a field coil |33. The voice coil and eld lat the time of the coil are connected to a removable plug |54 which maybe inserted in either the 4-'ohm socket |3| or the 8-ohm socket |35 asdesired. In case one only speaker is used, we may use the 8-ohm circuit.However, in case more than one speaker is desired, ire., an extensionspeaker, as may be desirable in any large public location, then bothspeakers are attached `to the 4-ohm winding in parallel.

Ampliers 55 and 55 are provided with positive D. C. by a power supplyconnection to a full wave rectifier tube |45 supplied by rectifierwinding |4| on power transformer 52?, and a recti- The output ofrecusual brute force filter comprising inductances |44 and shuntcapacities |45, this power supply having a positive leg |45 Supplyingtube |22 in amplifier 65, a leg |41 supplying the output tubes |25 and|25 in ampliiier 55, and a connection |48 supplying the anodes of thetubes IDL-|52, and |03 in amplifier 65. Field coil current is suppliedto eld coil |33 of speaker l0 through eld coil connection |45. A specialdisplay lamp winding 52D may be used to supply display lamps in cabinetI0, certain of which may be used to illuminate list I5.

Thus, at the outlying reproducer we have provided a microphone amplifierfeeding outwardly through a balancing network, a 60-cycle supply feedingoutwardly through the balancing network, and a speaker amplifier andspeaker receiving signals from the line 13 through the balancingnetwork,'a11 utilizing the same power supply.

` The action of the (iO-cycle coin switch will be de.-

scribed later.

In connection, however, with the main speaker amplier 55, it may bedesirable to incorporate therein an equalizer circuit and a basscontrol, in order to compensate for the acoustic characteristics whichmay exist in individual locations.- This may be accomplished as shown inFig. 5, where a tap |55 is taken from secondary |28 of outputtransformer |21, passed through a variable impedance circuit and thenceto the input grid |52 of input tube |22 of amplifier 55 through seriesresistors |53 and |54, the connection between the latter being groundedthrough capacity |55 and a variable resistor |56. Thus, in accorancewith the values of the variable impedance circuit |5| and resistor |55,various amounts of reverse feedback may be transferred to the input ofthe amplifier'in different frequency ranges and the bass response may beraised or lowered as desired. In most installations such a frequencyadjustment is made installation of the producer cabinet, and suchadjustments are not made available to the customer, or to any other thanservice:.men handling the entire distribution systemr- Having describedthe circuits utilized at outlying stations, we will now follow line intothe central station, the rst central station unit encountered being theisolation transformer 14 which feeds central station balancing network15. Central station balancing network 15 is shown in Fig. 6 and as thefrequencies passed are the sameas at the reproducing station the valuesof the network elements may be identical with those of the reproducingstation network and therefore these elements have been given the samenumber as used in the outlying reproducer network 51.

' on operating board 22. Thus,

former 51, which central station circuits as which shows however, onlytalking amplifiers 55r and 52, respectively, together with their powersupply. the phonograph amplifierY and the stepper relay circuits beingseparately shown.A

Outgoing voice signals 'initiated by Amicrophone 25 are passed intoresistance coupled ampliner 52 comprising cascadedtrlodes |55, |5|, and|52 coupled by resistor groups |53 and |54, the output tube |52 feedinginto switch 55 contacts 55T through output transformer |55, feeding intonetwork transformer 81 so that voice signals from microphone 25 mayenter the network 15 and thence be passed into the line 13. Incomingvoice signals from the line 13 enter the network 15 and are ,passedthrought network transformer 15 and thence through the listeningcontacts 55L of key 55 to input transformer |55 of listening amplifier55 comprising an input tube |51 feeding output tube |55, the latter,through an output transformer |55 feeding reproducers 25 in parallel.Tubes |51 and |58 are coupled by a resistance group |15. It may bedesirable to allow the central operator to control the gain of bothamplifiers 55 and 52, and if so, amplifier 85 is provided with a volumecontrol potentiometer |1|, which is placed on the front face 25 of theoperating boardv 22. Likewise, amplifier 52 may be provided with a voicevolume control potentiometer |12, and this may also be placed theoperator will be able to control at all times the outgoing voice volumeand the incoming voice and music monitor volume. In some cases it maybedesirable that the levels be changed slightly for different outlyingstations.

Both ampliers 52 and 85 are supplied from a conventional power supplycomprising a power transformer |55, a full wave rectifier tube |5| andfilter |52, a positive lead |53 supply both amplifiers. We also preferto use this same power supply to operate the impulse amplier 52 and forthis purpose provide a tap |54. Tap |54 may also supply the 60-cycleamplifier tubes in each stepper relay circuit, as described later. A.secondary winding |55 on transformer |55 supplies pilot lamps |85. Allreproducer amplifiers 58 are supplied by a power pack in rack 32.

The music signals sent out from the central station are taken off therecord by reproducer ing network feed shown in Fig. '1, the listeningand `85 and used to energize music amplifier 55 as shown in Figs. 10 and11. This is a high delity resistance coupled amplifier comprising inputtube |55 and output tube |5| couple-:l by resistance groups |52 and |58,the signal to output tube |5| being under the control of tap |54 on oneof the coupling resistors of `group |53. This amplifier is provided withthe usual output transformer |55 feeding into network transalso receivesvoice signals under the control of contacts A55T of switch 55.

Thus,'it will be seen that the phonograph pickup 85 is always connectedto its own line 13, ready for music signals transmission thereto. Thephonograph turntable motor 55 is under the control of arm switch|55,'and as previously explained, the operator is able to determinewhether or not the phonograph table is rotating, by the turntable pilotlamp 52 which is connected across motor 55 through transformer |51 onthe motor side of arm switch |55. In asmuch as arm switch |55 turns offturntable motor 55 when the end of the record is reached,

45-41 lthrough pilot line off lead |84 of the power supply feedingampliands turned onautomatically by the movement of the arm to aposition where the reproducer 89 starts the record playing, the operatoris at all times aware of the starting and stopping of each record.

Thus. we have described the circuits by which the operator may listento, 4and talk to each outlying station. It will also be obvious from thecircuits described so far, that the central station operator may notonly listen to any voice signals entering outlying station microphone66, but may also listen to the music being played through outlyingstation speaker 10, by echo. Inasmuch as the echo response of microphone66 will be low, a voice at the outlyingr station can be heard over it,and records requested eveny though a record is being played'. The60-cycle coin checking impulsesv ca n also be transmitted fiers 85 and92. The selected 60-cycle impulses are then passed to rectifier tube 222coupled to the grid 223 of a grid controlled gaseous conduction tube224. Such tubes are known in the art as ,thyratron impulse amplifiers,the action of which is well known. The anode 225 of thyratron tube 224is supplied through line 226 coming from a single wave rectifier tube221 supplied by a sec'- ondary 221a on power transformer 228, shown inFig. 8. This rectifier also supplies a bias circuit I225| forthyratrongrid 223. A low voltage winding 229a supplies the thyratron cathode.

'I'he output of the grid controlled gas tube' 224 is then passed througha coupling circuit 228d to the stepper relaysolenod 83, as shown in Fig.13. Stepper relay solenoid 83 attracts an arvvmature 23| attached to apivoted arm 232 having a terminal 233 engaging teeth 234 of relay disc235. Relay arm 232 is returned from the relay solenoid by return spring236. Relay disc 235 drives a relay switch arm 240 through a shaft 24|,this shaft being returned to zero position by a shaft spring 242, thisposition being determined b'y-pin 243. Remy switch arm 24o traversespilot light contacts 245, each connected with an indicator piidi iight'4o to n inclusive.

we wish it distinctly understood that there are i many types of coinswitches and that any type suitable for sending out interrupted currentin units will be satisfactory for this purpose. Fig. 12 is purelydiagrammatic and suggestive.

'I'he particular type of coin slide l2 shown diagrammatically in Fig. 12comprises a five cent coin slide 200, a ten cent coin slide 20|, and .atwenty-five cent coin slide 202 all projectingoutwardly from cabinet |0.Each slide has an appropriate coinreceptacle 203 therein. Inside rthecabinet an operating lever 204 is positioned with the end of each slide200, 20|, 202 in position to contactthe lever 204 at a differentdistance from lever pivot 206. The end of the lever 204 is provided witha pawl 201 held against .a ratchet wheel 208 by a spring 208. Ratchetwheel 208 is connected by a shaft 2|0 to a switch arm 2||, whichoperates over a stationary switch disc 2|2, having a plurality of spacedcontacts 2|3 thereon, all connected together, and to leg |09 of line |06(Fig. 4). Switch arm 2|| is connected to one leg of line 63, and thecontour of switch disc 2| 2 and the connection to disc 208 is such thatswitch arm 2|| always stops between two contacts 2|3. Thus,` when arm204 is moved by one of the coin slides 200, 20| or 202 moving inwardly,unlocked by the coin, the switch arm 2|| is rotated over one or morecontacts 2|3 as determined by the swing of the arm 204, thus gi-ving toline 63, 60-

cycle impulses in accordance with the value of the coin placed in thecoin slides. Arm 204 returns without rotating disc 2|2.

At the central station the (S0-cycle impulses pass through the balancingnetwork 15 into 60- cycle filter and rectifier unit 8| and stepper relaycontrol 82 in series, as shown in block in Fig. 3, and shown in detailin Fig. 9. The (iO-cycle signals pass to the filter 8| through networktransformer 18 and energize (iO-cycle amplifier tube 220 (Fig. 9), theanode circuit of which contains a Gil-cycle coupling circuit 22|. Thiscircuit 22| l by pushing buttonl 5|, the lamp current coming- The disc235 and switch arm 240 are held in position as determined by the numberof strokes of relay arm 232 yby latch 246, this latch being releasableby pushing on stepper relay release button 5| positioned'on theoperating board above pilot lights 40 to 41 inclusive. Thus, as thestepper relay operates, it moves switch arm 240 serially over the pilotlight contacts 245, and the last light remains lit until thel disc 235is released in over line |86. Thus, the pilot light lit corresponds inposition in the assembly to the accumulative ve cent unit value of the`coin inserted in coil slides 200, 20|, and 202, giving the operator adefinite check on the value of coins inis tuned sharply to 60 cycles andtherefore ex- L cludes 'other-frequencies, such as might comey in overthe line. Anode voltage for tube 220 is taken serted in the coin sh'le.

'In order to prevent unauthorized operation of the stepper relay,thereby falsely indicatingthe placing of coins in the coin slides,various units of the system as a whole are made insensitive to 60cycles.

' Referring to Fig. 3, it will be noted that balanc- `V ing network 61can be made sensitive to 60 cycles entering the network from the coinswitch. In order, however, to prevent false operation of the stepperrelay through energization of microphone 66 by 60-cycle sound, forexample, we may make amplifier 65 cut off well above 60 cycles, inasmuchas such lower voice frequencies are not necessary for voice clarity.Also, at the central station,

balancing network 15 may be made to have clear path for. 60 cycles intothe filter and rectifier units 8| and 82. Balancing network, however,can also be adjusted so that there is a poor transmission `of 60 cycleslaterally through the network, from network transformer 16, so thatadventitious (iO-cycle notes originating in either Amicrophone 25, voiceamplifier 82, -or the reproducer amplier 98 carrying music signals, willbe too low in value to` operate the stepper relay. Thus, it will be seenthat it is nowhere necessary to curtail the high fldelity of the musiccircuits. and that the cutoi existing in the outlying voice amplifiers65 is such that the .cutoff there in no Way impairs the ability ofA thevcentral station operator to understand the voice signals.

Thus, it will be seen that we have provided a system .which can bewholly operated over a single conductive pair connecting each outlying`station with the central station with full twoway voice communication,one-way 60-cycle communication and one-way music communication. Thecircuits as described have been so balanced as to allow two-way voicecommunication with perfect understanding even when music is being playedto an outlying station.` The voice level from the outlying station tothe central stav tion is such that the voice may readily be understoodover and above the echo pickup of the music, and the voice communication`from the central station back to the outlying loud-speaker is such thatit may be understood over and above the outgoing music. Furthermore, the60-cycle impulse path from the outlying station through to `the stepperrelay is operable, due to the use of tuned filter 22|, irrespective ofthe central station connections, and even during the playing of musicfrom the central station to the outlying station. This means, therefore,that any outlying station can, during the playing of a record, insertadditional coins to operate the stepper relay and, in spite of musicsignals on the line, gain the operators attention and tell 'the operatorthe numbers of additional selections without havingto stop the musicbeing played. Thus, the system is fool-proof as regardsnoin valueindication and voice communication even while the music is beingreproduced.

The circuits at the outlying reproducing stations are maintainedenergized at all times, except when the public location at which thereproducer 4is installed is closed. At that time a main switch may beopened in order that the reproducing station power supply transformer52P may be deenergized. This, of course, deenergizes the display lightsand the proprietor of the outlying station can the reproducer unit isenergized or not. The central station operator can easily tell whetherthe outlying station is alive'or not by listening on the particular lineconnected to the outlying station. II no extraneous noise is received,she may know the station is shut off; but if she desires, she can playmusic into the line and if no echo is received, she can be sure that thestation is cut off. Thus, at all times the central station operator hasfull control of, and full knowledge of, the circuit conditions at eachoutlying station.

In many cases it is desirable that coins to operate the outlying stationcabinet be inserted at points other than at the cabinet itself. Manytimes, such cabinets are used in public places where there are spacedand it is desirable under these circumstances that the system be capableof operation from a plurality of booth locations. Figs. 14 and l5 show acontrol circuit which is adapted to connect 'a number of auxiliarycontrol stations positioned at a` distance. from the cabinet. In Figs.14 and 16, the right-hand portion of the 4circuit represents the wiringinstalled in the speaker cabinet, and the left-hand portion of thediagram represents the circuit used at the remote control stations, suchas a booth or a plurality of booths, for example. It is believed thatthese circuits may be more clearly understood by a combined descriptionof the apparatus and operation thereof. All relay armatures in theseiigures are shown in resting positions.

. .The circuit shown in Fig. 14 is adapted to handle a plurality ofcoins at the cabinet, and a "single coin at a time only at the auxiliaryconeasily tell whether trol station. We will iirst describe the systemas operated from the cabinet.

A connection block 258 is provided, carrying lugs 25| and 252 acrosswhich coin switch 5| is connected. This coin switch may be the sameswitch as previously described for use in the speaker cabinet. The lug252 may be grounded. and lug 25| leads through relay 254 and thence tolug 255 on main connection block 255. Lug 255 has a companion lug 251adjacent thereto, and these two lugs are connected to a relay powersupply 255 through a. relay power switch 255. as shown in Fig. 15, thisswitch normally being y held closed. A momentary current flow for each'close, these contacts' 25| coin value caused by closure of coin switch5|, through relay 254, causes signal contacts 25| to being connectedthrough lugs 252 and 252 on block 255 to signaling line, as in themodiiication previously described. This energization 'of relay 254 alsocloses contacts 254 which control a circuit as follows: from' ground tocontact C on junction blocks 255-255 to contact C on second junctionblock 251, thence through strap 258 connecting lugs A-C, through thenormally closed contacts 255 of relay 218, on junction blocks 255 and255, through the closed contacts 254, thence through relay winding 21|,and thence to lug 255 on block 255, completing the energization of relay21|. Relay 21| then operates and holds by virtue of themake-before-break contacts 212 thereof until the relay power supply 255is interrupted by the operation of relay 214, opening power supplycontacts 250, as shown in Fig. l5. How relay 214 is operated will bedescribed later.

The holding of relay 21| opens the operating paths of relays 215 and 215so that these relays cannot be operated until relay 21| is released.Relay 21| also closes contacts 215 connecting power lug 255 to a busylamp wire 218 passing through junction blocks 255- 255, as lugs Bthereon, which lights the busy lamp 211 on block 218, at any remotecontrol station.

.At the speaker cabinet location, we provide a strap 280 which will alsoconnect a cabinet busy lamp 28| on the speaker cabinet, if desired.Thus, busy lamps 211 and 28| act as busy signals, so that if a coin isinserted at the cabinet location all of the busy lamps at auxiliarylocations will light. If desired, a busy lamp may be lit at the speakerlocation itself.

Relay 21| also operates microphone'contacts.

, 255, the other microphone connection 285 passing through contacts 252to lugs F on junction blocks 255-255 through normally closed contacts281 on relay 210 to lug F on plug 251, thence through strap 285 to lugsG on connection blocks 255, 255 back to microphone lug 255 on block 255.Lugs 285 and 258 are connected to microphone amplier 55 in the speakercabinet.

We may desire, however, to connect a strap 25| to contact 252, normallyclosed by relay 21|, so that contacts 282, 252. are connected together.This strap 25| when used, connects the cabinet microphone 55 to the lineat all times, except when an auxiliary location relay 215 is operated.This is so because strap 25| at al1 times closes contact 282 normallyoperated .by relay `21| so that the cabinet microphone 55 is energized'lrrespective of whether relay 21| is energized or not.

back through lugs .li4

dropped into cabinet coin switch 6|, relay 21| isV midtap of thetransformer leads to the cathode v 329 of tube 326 through a resistor330 shunted energized, cabinet microphone .66 Vis operating,

and busy lamps 28| and 21| are both illuminated when strap 280 is used.Once the central station operator has received her instructions viacabinet microphone 66 and checked her coin values, she then releasesrelay 21| by opening power supply relay contacts 260, as will bedescribed later, the busy lamps go out, and cabinet microphone 66 willremain energized or not, in accordance with whether or not strap 280 isused. l We will now describe the circuits that are utilized when thecoin is dropped in an auxiliary station. A single coin auxiliary switch300 is used, which is connected across lugs 30| and 302 on block 218.Dropping of a coin in auxiliary switch 300 causes a momentary current owfrom ground lug 251 through grounded lugs C on connection blocks 261,266, and`265. The current passes through strap 268 to lug A on block261. thence through normally closed contacts 265, thence to lugs A onconnection blocks 266 and 265, vthence through normally closed contacts305 on relay 21|, thence through relay winding 215, thence through lugsD on connection blocks 266,

by a capacity 33|. AGrids 332 and 334 of tube 326 are energized by thedivided secondary 335 of a signal transformer 336, the primary 331thereof being connected to line terminals 338 which are connected to theline at all times. yThe heater 340 Aoi" tube 326 is supplied byheaterwinding 34| on transformer 32|.

A relay control triode tube 342 is utilized, having the anode 343`thereof connected through power relay winding 214 to one side of A. Cmains 60. Winding 214 is preferably shunted by va condenser 345 and thegrid 346 of tube 342 is 265, thence through switch 300, thence throughrelay Winding 210, thence returning to the power supply through lugs Eon connection blocks 266 and 265, and nally to power supply lug 255 onblock 256. Relay 215 will close 60cycle contacts 306, which are parallelin 60cycle contacts 26| operated by relay 254, so that a momentary coinsignal 60cycle impulse will be sent out to the central station.AAuxiliary relay 210, however, whenenergized will hold because of itsmakebefore-break contacts until the power supply VCircuits areinterrupted by the operator to release relay 210. Relay 210 also opensthe operating paths of relays 215,254, and 21| so that these cannot beoperated until relay 210 is released. Relay 210 operatesA contacts 308which closes the busy lamp circuits at all locations. Relay 210 also,through contacts 295, connects the auxiliary microphone 294 to the lugs285 and 290 on block 256, and also by means of contacts 281 disconnectsthe cabinet microphone if it is continuously connected to the line bytheuse of strap 29|. This connection and disconnection being done by theshift from contacts 281 to contacts 295. o

Thus, it will be seen that we circuits which canbe extended as desired,so that a pluralityv of auxiliary stations, each comprising amicrophone, ,a coin switch. and a busy lamp, are interconnected so thatwhen the coin switch at the cabinet location, or at any auxiliarylocation, is operated, a busy vlamp will be shown at all otherlocations. All other microphones will be cut oi, and the operatedcircuit will hold.

until the operator at the central station releases it. One releasecircuit that may be utilized by the operator is shown in Fig. 15.

In the release circuit shown in Fig. 15, 60- cycle line 60 is connectedto the primary 320 of have provided y the transformer 32|, having adivided secondary 322. The ends of secondary 322' e'ad to anodes 324 and32s of a double diode tube 32s, and the 75 supplied from resistor 330 bymovable tap 341. In operation, 60cyclev current from the mains 60 issupplied to anode 343 of tube 342 and to anodes 324 and 325 of tube 326.This A. C. is in such phase that grid 346 is always negative when anode343 is positive, tap 341 onvresistor 330 being/moved until tube 342 isblocked. Under normal circumstances, connections 338, which are to theline, receive only signals comprising music, speech, and 60 cycles fromthe coin switch cir- Cuit. The 60-,cycle coin switch signals are appliedto grids 332 and 334 in such phase as to cause anodes 324 and 325 tocontinue to passv ing, as we prefer to use a condensor 33| acrossresistor 330 so that response is sluggish. When, however, the operatorat the central station desires to release the relay power switch 360,she sends out over the mainA lines a 60cycle signal of a phase oppositeto that of the 60cycle switch signals. This reverse phase 60cycle signalreaches grids 332 and 334 of tube 326 in proper phase to drive grids 332and 334 cyclically negative when anodes 324 'and 325 are positive, thusblocking the tube 326. Tube 326, being blocked, can pass no currentthrough resistor 330, thus removing the negative potential on grid 346of tube 342 and allowing tube 342 to pass current. This current passesthrough relay winding 214, opening switch 260 for a period coincidingsubstantially with the reverse phase signals sent out by the centraloperator. As soon as the holding relays 210 and 21| have had time torelease, the central oflice signal is stopped, switch 260 recloses andthe control locations are ready for a new coin insertion. Thus, it willbe seen that we have provided a system where the locally generated60cycle signals, and music and voice sig' nals, will not operate therelay power supply switch 260,*but where a central station 60cyclesignal in proper phase will operate it. We have found thatin therelatively short telephone pairs used between central and outlyingstations, no appreciable phase rotation occurs, and that exact phasereversal is not necessary to operate the release relay. o

In Fig. 16, we have shown a modication of the circuit of Fig. 14 whereall coin values may be inserted both at the cabinet, or at any of theauxiliary stations. In view of the rather complete description of Fig.14 given herein, it is not believed necessary to follow through thecircuits in detail in Fig. 16. The main differences between the circuitof Fig. 14 'and that of Fig. 16 are that the signal relay 215 shown atthe cabinet location in Fig. 14 is omitted in the circuit shown in Fig..16, and a relay 254 is used at all auxiliary stations. Two additionallugs are added to conmuon blocks m, m, and m w camine eocycle signalline into all of the auxiliary locations to relays 284. Thus, relays 2Mdirect the 'coin signals to the main lines directly from the cabinetlocations and from all auxiliary locations. Relays 2'Ii hold in exactlythe same manner as they did in the circuit of Fig. 14, and otherwise theoperation of the system is the same. Thus, it will be seen that thecircuit of Fig. 16, at each auxiliary location is a substantialduplicate of the cabinet circuit of Fig. 14 with 254 added at eachauxiliary location.

We claim:

1. In a wired music system, a central station and an outlying station, aline having two conductors only connecting said stations, a balancingnetwork `at eachstation and connected to said line, a high iidelitysound reproducing circuit fed from the outlying station network, amicrophone circuit feeding into said outlying station network, means iorfeeding separate 60-cycle impulses into said outlying station networkand thence into said line, a 60-cycle impulse ampliner circuit fed fromthe central stasignal relay 21| l .omitted and a separate keying andcontrol relay networks terminating wherein said an operating worksterminating a plurality of two-wirelines from a plurality or mitlylngstations, wherein a single talking circuit and'a single voice reprotionnetwork, \a step relay actuated by and in accordance with the number ofamplied 60- cycle impulses, indicator lamps serially lighted by saidrelay, a phonograph record pickup circuit feeding into said centralstation network, and talking and voice receiving circuits connectible atwill to said pickup and (l0-cycle circuits respectively in response toindicator lamp illumination.

2. Apparatus in accordance with' claim 1 wherein a coin switch isprovided and means are' provided to feed 60-cycle energy into saidoutlying station network and said line in implilses corresponding innumber to the ve cent unit value of the coins passed through said coinswitch.

3. Apparatus in accordance with claim 1 wherein a coin switch isprovided and means are provided to feed (S0-cycle energy into saidoutlying station network and said line in impulses corresponding innumber to the 'iive cent unit value of the coins passed through saidcoin switch and wherein the lamp lighted by said step relay indicatestotal coin value.

4. Apparatus in accordance with claim 1 wherein'said 60-cycle impulseamplier comprises circuit means for excluding other than 60- cyclesignals, a rectiiler oi' signals passed, and a grid controlled gaseousdischarge tube controlled by said rectified signals for operating saidstep relay.

5. Apparatus in accordance with claim 1 wherein said central station isprovided with an operating board containing central station networksterminating a plurality of two-wire lines from a plurality of outlyingstations, and wherein a single talking circuit and a single voicereproducing circuit are connectible at will to any one of the centralstation networks.

6. Apparatus in accordance with claim 1 wherein said central station isprovided with an operating board containing central station networksterminating a plurality of two-wire lines from a plurality of outlyingstations, wherein a single talking circuit and a single voice reproduc--ing circuit are connectible at will -to anyone of the central stationnetworks, and wherein the indicator lamps controlled by each network aregrouped in separate areas on said board and in a predetermined orderthereon.

7. Apparatus in accordance with claim 1 ducing circuit are connectible'at will to any one of the central station networks, wherein theindicator. lamps controlled by each network aregroupedinseparateareasonsaidboardandin a predetermined order thereon,wherein each phonograph pickup is actuated by a record turntable anddriving motor thereior, and wherein a signal lamp energized in parallelwith each motor is positioned adjacent the lamp group connected to the,same network as said pickup.

9. A system for signaling over a line having two conductors onlycarrying heterogeneous audio frequencies which comprises, a music signalgenerator connected to one end of said line, a music signal reproducerconnected to the other end of said line, a 60cycle impulse generatorconnected to the signal reproducer end of said line and a 60-cycleimpulse indicator connected to the signal generator end or said line. anetwork at the reproducer end of said line for providing a relativelyhigh impedance path between said impulse generator and said signalreproducer, and a second network means at the signal generator end ofsaid line for providing a relatively high impedance path between saidmusic signal generator and said impulse indicator.

10. Apparatus in accordance with claim 9 wherein a continuouslyenergized microphone circuit is connected to the network at the signalreproducer end of said line in parallel with said impulse generator, andwherein saidmicrophone circuit ls ltered to exclude 60cycle voicecurrents.v

11. Apparatus in accordance with claim 9 wherein a continuouslyenergized microphone circuit is connected to the network at the signalreproducer end of said line in parallel with said impulse generator,wherein said microphone cir'v cuit is iiltered to exclude 60-cycle voicecurrents, and wherein a listening circuit is connected ,at will to thesecond network in parallel with said impulse indicator.

12. Apparatus in accordance with claim 9 wherein a continuouslyenergized microphone circuit is connected to the network at the signalreproducer end of said line in parallel with said impulse generator,wherein said microphone circuit is ltered to exclude (l0-cycle voicecurrents, and wherein said impulse generator is coin actuated.

13. Apparatus in accordance with claim 9 wherein a continuouslyenergized microphone :circuit is connected to the network at the signalreproducer end or said line in parallel with said impulse generator.wherein said microphone circuit is altered to exclude 60-cgcle voicecurrents.

wherein a listening circuit is connected at will to the second networkin parallel with said impulse indicator, and wherein said impulsegenerator is coin actuated.

14. The method of signaling over a two-wire line carrying music signalswhich comprises connecting a music signal reproducer and an imducer andof said line, :feeding into said line Impulse generator to one end ofsaid line through a network providing a relatively high impedance pathbetween said generator and said reproducer, a relatively low impedancepath between both and said line connecting a music signal generator andan impulse receiver to the other end of said line through a secondnetwork providing a relatively high impedance path between said signalgenerator and said impulse receiver, and a relatively low impedance pathbetween both the latter and said line whereby both signal transmissionand impulse transmission may simultaneously take place over said line.

15. Method in accordance with claim 14 wherein said impulse generator isintermittently operated and wherein voice signals are supplied to saidline over the 60-cyc1e impulse path.

16. Apparatus in accordance with claim 9 wherein a plurality ofmicrophones are provided at spaced locations at the music signalreproder control of a holding-relay associated with a coin switch ateach location, said holding relay disconnecting all the remainingmicrophones, and a holding relay power supply controlled by cyclesignals originating from the other end of said line and in a phaseopposite tothe 60-cycle signals generated at said music signalreproducciend ofsaid line. l l

17. Apparatus lin accordance with claim 9 wherein a plurality ofmicrophones are provided at spaced locations at the music signalreproducer end of said line, feeding into said line under control of aholding relay associated with a coin switch at each location, saidholding relay disconnecting all the remaining microphones, and a holdingrelay power simply controlled by 60- cycle signals originating from theother end o! said line and in a phase opposite to the fio-cycle signalsgenerated at said music signal reproducer end of said line, said holdingrelays also controlling a circuit lighting a busy lamp at all microphonelocations other than that where said coin switch is operated.

, LEONARD L. LEYRER.

ROBERT L. STARK.

